Patrick Blanc’s vertical gardens at One Central Park, a new apartment complex in Sydney’s inner western suburb of Ultimo, span 1000 square metres and sprawl across the building’s two towers, which are 16 and 33 stories high. At 150 metres high, they are the tallest vertical gardens in the world. Comprising 21 panels, 30,000 shrubs and 70,000 plants–totalling nearly 360 mostly native species, with many drawn from Australia’s south-eastern region of Wentworth Falls–the vertical gardens will appear, in Blanc’s words, “like a natural cliff, as though [one has] cut a giant slice out of the Blue Mountains and put it in the middle of the city.” The greening process for the vertical gardens began in October 2012.

AIMS

Cultural

Visual & Aesthetic: Patrick Blanc’s vertical gardens aim to show how nature can be integrated into urban living and densely populated areas. Blanc argues, “Vertical Gardens are not a criticism [of] the city and concrete is not pushing nature further away. It brings man closer to nature.” Vertical gardens occupy otherwise unexploited areas of the city to provide a sustainable alternative to horizontal gardens.

Social

Skills Acquisition: By collaborating with Blanc to realise One Central Park’s vertical gardens, Aspect Oculus will build extensive new knowledge in this relatively new and technically complex, field of landscape architecture and design.

Environmental

Energy Efficiency or Generation and Air quality: Blanc’s vertical gardens are part of a much larger green project. One Central Park aims to set a new benchmark for sustainable building and architecture. It will adopt state of the art environmental management and energy efficient components during the design and construction of the building. The building has a 5 out 6 possible GreenStar rating, which aims to be further developed through the implementation of Blanc’s Vertical Gardens. As Blanc states, “Thanks to its thermic isolation effect, the Vertical Garden is very efficient and aids in lowering energy consumption both in winter, by protecting the building from the cold, and in summer, by providing a natural cooling system.” Blanc’s Vertical Gardens also act as natural air purification system. The gardens’ felt absorbs polluting particles from the air and slowly decomposes and mineralizes them, transforming them into plant fertilizer.

Economic

Marketing/Place and Identity, Regeneration, and Attracting Investment and Jobs:Blanc’s One Central Park vertical gardens are part of a larger regeneration program taking place in the Central Park zone of Sydney’s inner western suburbs. Led by Frasers Property and situated in the abandoned Carlton & United Brewery, Central Park will comprise 11 buildings, 2,000 apartments, numerous retail outlets, laneways, terraces and a 6,400 square metre community park. The complex will aim to be an “icon of twenty-first century living”, providing a vibrant social and commercial hub while simultaneously instilling a “village green” and practicing sustainable architecture and urban planning. Given that the vertical gardens will require extensive maintenance, it is also expected that, like the vertical garden at the Trio apartment complex in Sydney’s inner suburb of Camperdown, the project will provide jobs for the Australian landscape architecture industry.

OUTCOMES & IMPACTS

Cultural

After the success of Blanc’s vertical garden at Trio, and due to the international renown of the artist-botanist, Blanc’s project One Central Park has received much positive media attention in major broadsheets and specialist architecture/design magazines and blogs.

Economic

While it is too early to assess the economic benefits of Fraser Property’s regeneration project at Central Park, to date it has sold 532 out of 623 of its apartments at One Central Park.

PROJECT DELIVERY

In 2009 Frasers Property commissioned Patrick Blanc to complete a series of vertical gardens for One Central Park. The commission followed the success of Blanc’s vertical garden at Frasers Property’s Trio apartment complex in Camperdown (Sydney), completed in 2010.

Blanc and Aspect Oculus face several challenges in creating the tallest vertical gardens in the world for One Central Park. The plants need to be both carefully selected and positioned to thrive. To select the plants, in 2009 and 2011 Blanc undertook several fieldtrips to the Blue Mountains, the Royal National Park and Tasmania’s Cradle Mountain. To position the plants, Aspect Oculus drew up a colour-coded plan of One Central Park’s facade detailing its different zones of exposure to the wind and sun. Moreover, in order to ensure that the garden will be able to sustain its high elevation and gale-force winds, as well as heat waves and high levels of humidity typical of Sydney’s climate, Aspect Oculus put the garden’s proposed plant species under strenuous tests at the St. Peters wind tunnel laboratory. The vertical garden’s height of 150 metres proposes significant mechanical challenges to the project. As Blanc explains:

You can have dehydration of the leaves, so you have to choose smaller leaves so they are more resistant to the wind. And you cannot choose plants with longer stems which can break; you cannot choose those with bigger flowers.

IMPACTS OF ARTWORK PRODUCTION

(Based on an interview with Patrick Blanc).

What consideration went in to the selection of materials? Was an effort made to source materials that were more sensitive to the environment?

For this living artwork, the most important material are the plants themselves. In order to reduce the maintenance and its energy cost, I decided to have a very high level of biodiversity. I chose 370 species, 200 of them being native from south-east Australia. This high biodiversity is important to reduce the nutrient and water amount needed for the global growth of the different species and there is no need to use pesticides or chemicals as no insect or disease damage arise, due to this high level of biodiversity. Moreover, my totally mingled design of the distribution of the species on the vertical gardens is the best warranty of low maintenance. Actually, I work in this way since my first vertical gardens, now more than 30 years ago.

Was any effort made to measure the environmental impacts of the construction and maintenance of the work, in terms of:

- Energy use in operation and construction?

All the plants came as small and very light tub plants from different nurseries but have been grown during one year in a single nursery close to Sydney in order to reduce the travel energy expenses due to quite heavy containers and long distances. All the materials have been purchased locally except the felt (the growing medium for the roots and the associate microorganisms) which has been imported from France by boat: this medium is made from old recycled polyamide clothes and is thus non-biodegradable. That means that no maintenance is needed to change this medium after some years and the oldest medium with plants growing vertically on it is in my home and is now 31 years old, without any change. In order to reduce the energy use during the in situ installation of the vertical garden panels, all the assemblages (structure, irrigation and my plant designs) have been manufactured at the ground level and the panels are installed at the same time as the other parts of the facades and they are growing up with the façades themselves. Only the plants are installed when everything is ready to ensure their best way of life. For the maintenance, this will be done from the upper gondolas, in the same way as the cleaning of the glass façades. This will be done only three times a year.

- Travel during the construction phase?

For me, no special travel during the construction phase (my last travel, two months ago, was actually decided because I had to go in Queensland). Of course, such an exceptional and amazing project needed already my presence about five times to choose the right species in the right nurseries, also to discuss with architects and owners and finally for conferences (for instance a conference invited by Madame Clover Moore on 1st December 2009).

- Embodied energy and other life-cycle impacts of the materials used?

The recycled polyamide growing medium is issued from petrol as well as the expanded PVC. Concerning the plants, their growth is a CO2 capture. Otherwise, the capture of VOC compounds is enhanced by the direct contact of the growing medium to the air and its thin thickness (two layers 3 mm thick) allows the best development for the microorganisms responsible of the VOC degradation and the absoption of their resultant molecules by the roots of the plants.

Was there any innovation in the use of materials or processes that were more environmentally friendly than the alternatives?

Concerning the processes, just as explained above, most of the preparation work has been done at the ground level. All the water used for the vertical gardens and the other plant installation is collected from the site (roofs, open areas) and also from all the grey (and black) waters collected, treated and recycled, issued from the two towers.

Is the environmental footprint of the work in keeping with the aims and intent of the artwork?

Perfectly. The environmental footprint will be positive: use of recycled water, growth of the plants with carbon capture, air purification, high biodiversity level, welfare of people both inside the apartments and walking in the street. Finally, the artistic design involving so many species is the best warranty for the lowest environmental footprint.

This database is developed by the National Institute for Experimental Arts (NIEA) at COFA, UNSW in association with the City of Sydney and Carbon Arts as part of the Australian Research Council ARC linkage project Curating Cities.